"It was a very tough task for me today, especially if everything was going his way," Dimitrov said. "I just couldn't find the rhythm, and I couldn't [convert] any of the little opportunities that I had in the match. So it's something to obviously learn from, but in a way was one of those days that you can't control anything. It happens."

Both men came into the first-round match playing the best clay court tennis of their careers. Dimitrov won his first clay title this spring in Bucharest, and then reached the fourth round of the Monte Carlo Masters and the Madrid Open before making his first ATP Masters 1000 semifinal two weeks ago at the Italian Open (and beating Karlovic in the second round). Karlovic, on the other hand, made the final of last week's warm-up event in Dusseldorf.

Ivo Karlovic is feeding off of his strong week in Dusseldorf. (Matthew Stockman/Getty Images)

"Last week was definitely was a big push in my clay court season because I didn't do really well on clay since I don't even remember when," Karlovic told SI.com. "It was an excellent week and it rolled into here. Today was one of my best matches on the clay court."

"Today he was all over the court," Dimitrov said. "He was just hitting his shots, penetrating every volley, low slice, serving really good... Even though I tried a lot of things, it is what it is. At the end of the day I don't want to get myself too down for that. It's just a loss."

Karlovic didn't blink when he saw that he drew Dimitrov. Though he's never made it past the second round at Roland Garros, he feels like he's playing with house money.

"I already did well last week so I didn't really care because it's clay court and it is not my best surface. But today I felt really good and just hit every ball, and tactically, I did really well."

Dimitrov, who was drawn into Rafael Nadal's quarter, was projected to face David Ferrer in the fourth round. Now, the only remaining seeds in that section are Ferrer, Kevin Anderson and Andreas Seppi.

As for Karlovic's thoughts on his own chances of making it that far? He's not really thinking about it.